Peroxidic compositions and process for the preparation thereof



United States Patent 3,546,249 PEROXIDIC COMPOSITIONS AND PROCESS FORTHE PREPARATION THEREOF Hans G. Gerritsen and Arnold Schroeder,Deventer,

Netherlands, assignors to Koninklijke Industrieele Maatschappij N oury &van der Lande N .V., Deventer, Netherlands, a corporation of theNetherlands No Drawing. Filed Feb. 19, 1968, Ser. No. 706,608 Claimspriority, application Netherlands, Feb. 21, 1967, 6702570 Int. Cl. C07d19/00; C07c 73/00, 73/06 US. Cl. 260338 8 Claims ABSTRACT OF THEDISCLOSURE Peroxidic compositions are provided which are useful, e.g.,.as initiators for polymerizing unsaturated polyester resins fromunsaturated polyesters and monomers containing one or more CH =C groupssuch as, e. g., styrene. The peroxidic compositions are obtained byreacting diacetone alcohol with an aqueous solution of hydrogen peroxideunder certain rather closely specified reaction conditions.

This invention relates to the preparation of peroxidic compositions andis especially concerned with compositions of a peroxidic nature whichcan be used in the polymerization of unsaturated polyester resins.

It is well known that unsaturated polyesters may be copolymerized with anumber of monomeric substances with the aid of free-radical-liberatingcompounds, and, particularly, organic peroxides, in order to produceunsaturated polyester resins.

The term unsaturated polyester resins is to be understood herein asmeaning mixtures of or derived from unsaturated polyesters and monomerscontaining one or more CH =C lgroups.

Unsaturated polyesters are obtained by reacting a polyhydric alcohol,for example, a dihydric alcohol such as ethylene glycol, propyleneglycol or diethylene glycol, or a mixture of polyhydric alcohols, withan unsaturated dicarboxylic acid, for example maleic acid, fumaric acidor itaconic acid; and if desired, in the presence of a saturateddicarboxylic acid, for example malonic acid, adipic acid, sebacic acid,tartaric acid, phthalic acid, isophthalic acid or tetrachlorophthalicacid.

Styrene, vinyl toluene, vinyl chloride, vinyl acetate andmethylmethacrylate are mostly used as copolymerizable monomers in thepreparation of unsaturated polyester resins. Generally, the ratiobetween the monomer and the unsaturated polyester in the mixture rangesfrom 3050 parts by weight of the monomer to 70-50 parts by weight of theunsaturated polyester.

If it is desired to carry out the copolymerization of the monomer withthe unsaturated polyester at room temperature, accelerators are added tothe mixture to be copolymerized, in addition to organic peroxides, inorder to cause rapid decomposition of the peroxides into free radicalsat the temperature employed. Cobalt octoate, vanadium naphthenate andmanganese compounds are used as such accelerators.

In British Patent No. 937,166, a process for the preparation ofbis-3-(3,5,5-trimethyl-l,2-dioxolanyl)peroxide (mesityl oxide peroxide)is described wherein diacetone alcohol is reacted in an aqueous mediumwith hydrogen peroxide in a molar ratio of about 2:3 in the presence of3,546,249 Patented Dec. 8, 1970 about 3.75 gram-equivalents of sulphuricacid per mol of diacetone alcohol. In British Pat. No. 937,165, thisperoxide is recommended as an activator in polymerization reactions.Under normal circumstances, however, an unsaturated polyester resin doesnot gel with this peroxide, not even in the presence of an accelerator.Therefore, mesityl oxide peroxide has not found practical application sofar.

In accordance with the present invention, it has now been found that aperoxidic composition suitable for the peroxidic copolymerization ofunsaturated polyester resins and essentially consisting, as regards theperoxides present, of peroxides derived from diacetone alcohol, may beobtained by reacting diacetone alcohol with an aqueous solution ofhydrogen peroxide in such a quantity that the molar ratio between theketone alcohol and the hydrogen peroxide is equal to or more than 122,and preferably 1:1, at a temperature ranging from l050 C. in thepresence of 1-20, preferably l-S, milligram equivalents of a completelyor almost completely dissociated acid per mol of diacetone alcohol, andsubsequently adjusting the reaction mixture to a pH of 3-5, andpreferably a pH of 44.5.

It is presumed that in the composition water-soluble peroxides areformed having the following general formulae:

n and m=0, l or 2; and 1:2 or 3.

The peroxidic composition according to the present invention can be usedto effect a quicker hardening of the unsaturated polyester resins than,for instance, methyl ethyl ketone peroxide. Moreover, the copolymerizedun saturated polyester resins obtained have a high heat-distortiontemperature due to the fact that the composition according to thepresent invention is applicable directly, that is to say without addingplasticizers.

The hydrogen peroxide required for the preparation of the compositionaccording to the present invention may be added in the form of a 35%,50%, or by weight solution. For economical reasons, however, a 50% or70% by weight solution is preferred.

Sulphuric acid, phosphoric acid, toluene sulphonic acid and alsostrongly acid ion exchangers, such as commercially available Dowex 50W-K 8, may be used as catalyzing acids.

In order to adjust the reaction mixture to the desired pH of 3-5, alkalimetal hydroxides, ammonium hydroxide, alkali metal or alkaline earthmetal carbonates, primary and secondary amines and amino alcohols may beused.

Although not necessary, inert solvents may be added to the compositionaccording to the present invention, if desired. The reaction between theketone alcohol and the peroxide may also be carried out in an inertsolvent. Inert solvents include dimethyl or dioctyl phthalate, trimethylor triethyl phosphate, hexylene glycol, polyoxyethylene alcohols andtheir ethers.

In order that the invention may be still more readily understood, thefollowing detailed working examples are given:

EXAMPLE I A mixture of 68 g. of 50% by weight hydrogen peroxide (1 mol)and 1 ml. of 2 N sulphuric acid (2 milligram equivalents per mol ofketone alcohol) was added with stirring to 116 g. (1 mol) of diacetonealcohol in 30 minutes. The temperature of the reaction was kept at 25 C.by cooling. After 4 hours of stirring, the pH of the reaction mixturewas adjusted to 4-4.5 by the addition of 3.8 ml. or 0.5 N sodiumhydroxide solution. The composition obtained (180 g.) had a total activecontent of 8.34% (98.8% of the quantity introduced). The activeO-content organically bound was 4.05%.

EXAMPLE II A mixture of 48.5 g. of 70% by Weight hydrogen peroxide (1mol) and 1 ml. of 2 N sulphuric acid (2 milligram equivalents per mol ofketone alcohol) was added with stirring to 116 g. (1 mol) of diacetonealcohol in 20 minutes. The temperature of the reaction mixture was keptat 20-25 C. by cooling. After 4 hours of stirring at this temperature,the pH of the reaction mixture was adjusted to 4.1 by the addition of3.7 ml. of 0.5 N sodium hydroxide solution. The composition obtained(169 g.) had a total active O-content of 9.33% (98.5% of the quantityintroduced). The active O-content organically bound was 5.1%. When usewas made of 350 mg. p.toluene-sulphonic acid.O.aq. (2 milligramequivalents per mol of ketone alcohol), instead of 1 ml. of 2 Nsulphuric acid, and 2.6 ml. of 0.5 N sodium hydroxide solution, the pHbeing adjusted to 4.1, a composition (167.5 g.) was obtained having atotal active O-content of 9.34% (98% of the quantity introduced). Theactive O-content organically bound was 5.5%.

EXAMPLE III A mixture of 40.8 g. 83.3% by weight hydrogen peroxide (1mol) and 1 ml. of 2 N phosphoric acid (2 milligram equivalents per molof ketone alcohol) was added with stirring to 116 g. (1 mol) ofdiacetone alcohol in 30 minutes. The temperature of the reaction mixturewas kept at 20-25 C. by cooling. After 4 hours of stirring, the pH ofthe reaction mixture was adjusted to 4-45 by the addition of ml. of 0.15N sodium hydroxide solution. The composition obtained (168 g.) had atotal active O-content of 9.35% (98% of the quantity introduced). Theactive O-content organically bound was 7.15%.

EXAMPLE IV Using a polyester resin consisting of 70% by weightunsaturated polyester and 30% by weight styrene, mixtures were madecontaining the initiators and accelerators tabulated hereafter in thequantities stated. The unsaturated polyester employed herein forreaction with the styrene was prepared by esterifying 1 mol of fumaricacid and 1.1 mol of ortho-phthalic acid with 1.1 mol ethylene glycol and1.1 mol propylene glycol at a tem- 4 perature of 140 to 200 C., in thepresence of a current of CO as a sweep gas, until an acid value of 40 isobtained for the unsaturated polyester.

The gel-times of the mixtures obtained were determined at 20 C. and alsothe hardening, which was measured according to the Persoz hardness.

Parts by weight Polyester resin 100 100 100 Peroxide according to thepresent invention 2 Mesityl oxide peroxide 1 2 Methyl ethyl ketoneperoxide 2 2 Conventional cobalt accelerator (1% cobalt) 0.25 0.25 0.Gel-time in minutes 7 l6 Persoz hardness after stated time:

32 days- 1 Content 100%. 2 In dimethyl phthalate, active O-content 9.2%.At 60 C. the gel-time was 360 minutes.

EXAMPLE V 100 parts by weight of a polyester resin consisting of 70% byweight unsaturated polyester (prepared as described above in Example IV)and by weight styrene were mixed with 4 parts by weight of the peroxidiccomposition prepared according to Example I and 0.5 part by weight of aconventional cobalt accelerator containing 1% by weight of cobalt.

The heat-distortion temperature of the resin (measured according to theASTM-method D 648) was 72 C.

When use was made of 4 parts by Weight of a methyl ethyl ketone peroxidesolution in dimethyl phthalate (active O-content 9.2%) instead of theperioxidic composition according to the present invention, theheatdistortion temperature was C.

While specific examples of preferred methods and compositions embodyingthe present invention have been set forth above, it will be understoodthat many changes and modifications may be made in the methods ofprocedure and in the compositions without departing from the spirit ofthe invention. It will therefore be understood that the examples citedand the particular proportions and methods of operation and thecompositions set forth above are intended to be illustrative only, andare not intended to limit the scope of the invention.

What is claimed is:

1. A process for preparing a peroxidic composition, which comprisesreacting diacetone alcohol with an aqueous solution of hydrogen peroxidewherein the molar ratio of the ketone alcohol to the hydrogen peroxideis equal to at least about 1:2, at a temperature in the range from about10-50 C., in the presence of about 1-20 milligram equivalents of acompletely or almost completely dissociated acid per mol of diacetonealcohol, and subsequently adjusting the pH of the reaction mixture to avalue of about 3-5.

2. A process according to claim 1, in which the molar ratio of theketone alcohol to the hydrogen peroxide is about 1:1.

3. A process according to claim 1, in which the reaction is carried outin the presence of about 1-5 milligram equivalents of acid per mol ofthe diacetone alcohol.

4. A process according to claim 1, in which the pH is adjusted to avalue of about 44.5.

5. A process according to claim 1, in which the acid used is sulphuricacid or phosphoric acid.

6. A process according to claim 1, in which a 50% or by weight aqueoushydrogen peroxide solution is used.

7. A process according to claim 1, in which the reaction is carried outin an inert solvent.

8. A peroxidic composition, consisting essentially of 6 peroxides derivad from djacetone alcohol, prepared by a FOREIGN PATENTS Pmess acwrdmgClam 937,166 9/1964 Great Britain.

References Cited NORMA s. MILESTONE, Primary Examiner UNITED STATESPATENTS 5 US. Cl. X.R. 3,047,406 7/1962 Ferrarl et a1. 260610X 260 6103,160,667 12/1964 Higashiuchi et a1. 260610

